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revision 185 by ph10, Tue Jun 19 13:39:46 2007 UTC revision 276 by ph10, Wed Nov 21 15:39:20 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 19-June-07  Version 7.5 12-Nov-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    
49    Version 7.4 21-Sep-07
50    ---------------------
51    
52    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
53        means that a class such as [\s] counted as "explicit reference to CR or
54        LF". That isn't really right - the whole point of the change was to try to
55        help when there was an actual mention of one of the two characters. So now
56        the change happens only if \r or \n (or a literal CR or LF) character is
57        encountered.
58    
59    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
60        of both had grown to the point where there were only 3 bits left.
61        Fortunately, there was spare space in the data structure, and so I have
62        moved the internal flags into a new 16-bit field to free up more option
63        bits.
64    
65    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
66        but did not set the internal JCHANGED flag - either of these is enough to
67        control the way the "get" function works - but the PCRE_INFO_JCHANGED
68        facility is supposed to tell if (?J) was ever used, so now (?J) at the
69        start sets both bits.
70    
71    4.  Added options (at build time, compile time, exec time) to change \R from
72        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
73    
74    5.  doc/pcresyntax.html was missing from the distribution.
75    
76    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
77        compatibility, even though it is no longer used.
78    
79    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
80        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
81        windows.h file is present (where different names are used). [This was
82        reversed later after testing - see 16 below.]
83    
84    8.  Changed all #include <config.h> to #include "config.h". There were also
85        some further <pcre.h> cases that I changed to "pcre.h".
86    
87    9.  When pcregrep was used with the --colour option, it missed the line ending
88        sequence off the lines that it output.
89    
90    10. It was pointed out to me that arrays of string pointers cause lots of
91        relocations when a shared library is dynamically loaded. A technique of
92        using a single long string with a table of offsets can drastically reduce
93        these. I have refactored PCRE in four places to do this. The result is
94        dramatic:
95    
96          Originally:                          290
97          After changing UCP table:            187
98          After changing error message table:   43
99          After changing table of "verbs"       36
100          After changing table of Posix names   22
101    
102        Thanks to the folks working on Gregex for glib for this insight.
103    
104    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
105        unicode-properties was also set.
106    
107    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
108    
109    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
110        checked only for CRLF.
111    
112    14. Added casts to pcretest.c to avoid compiler warnings.
113    
114    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
115    
116    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
117        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
118        entirely. This removes changes made in 7 above.
119    
120    17. The CMake files have been updated, and there is now more information about
121        building with CMake in the NON-UNIX-USE document.
122    
123    
124    Version 7.3 28-Aug-07
125    ---------------------
126    
127     1. In the rejigging of the build system that eventually resulted in 7.1, the
128        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
129        brackets there is not right, since it causes compilers to look for an
130        installed pcre.h, not the version that is in the source that is being
131        compiled (which of course may be different). I have changed it back to:
132    
133          #include "pcre.h"
134    
135        I have a vague recollection that the change was concerned with compiling in
136        different directories, but in the new build system, that is taken care of
137        by the VPATH setting the Makefile.
138    
139     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
140        when the subject happened to end in the byte 0x85 (e.g. if the last
141        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
142        characters but of course it shouldn't be taken as a newline when it is part
143        of another character. The bug was that, for an unlimited repeat of . in
144        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
145        characters when looking for a newline.
146    
147     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
148    
149     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
150        in debug output.
151    
152     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
153        long printing in the pcrecpp unittest when running under MinGW.
154    
155     6. ESC_K was left out of the EBCDIC table.
156    
157     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
158        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
159        limit also applies to "virtual nesting" when a pattern is recursive, and in
160        this case 1000 isn't so big. I have been able to remove this limit at the
161        expense of backing off one optimization in certain circumstances. Normally,
162        when pcre_exec() would call its internal match() function recursively and
163        immediately return the result unconditionally, it uses a "tail recursion"
164        feature to save stack. However, when a subpattern that can match an empty
165        string has an unlimited repetition quantifier, it no longer makes this
166        optimization. That gives it a stack frame in which to save the data for
167        checking that an empty string has been matched. Previously this was taken
168        from the 1000-entry workspace that had been reserved. So now there is no
169        explicit limit, but more stack is used.
170    
171     8. Applied Daniel's patches to solve problems with the import/export magic
172        syntax that is required for Windows, and which was going wrong for the
173        pcreposix and pcrecpp parts of the library. These were overlooked when this
174        problem was solved for the main library.
175    
176     9. There were some crude static tests to avoid integer overflow when computing
177        the size of patterns that contain repeated groups with explicit upper
178        limits. As the maximum quantifier is 65535, the maximum group length was
179        set at 30,000 so that the product of these two numbers did not overflow a
180        32-bit integer. However, it turns out that people want to use groups that
181        are longer than 30,000 bytes (though not repeat them that many times).
182        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
183        made it possible to implement the integer overflow checks in a much more
184        dynamic way, which I have now done. The artificial limitation on group
185        length has been removed - we now have only the limit on the total length of
186        the compiled pattern, which depends on the LINK_SIZE setting.
187    
188    10. Fixed a bug in the documentation for get/copy named substring when
189        duplicate names are permitted. If none of the named substrings are set, the
190        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
191        empty string.
192    
193    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
194        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
195        because the ] is interpreted as the first data character and the
196        terminating ] is not found. PCRE has been made compatible with Perl in this
197        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
198        cause memory overwriting.
199    
200    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
201        string has been matched (to stop an infinite loop). It was not recognizing
202        a conditional subpattern that could match an empty string if that
203        subpattern was within another subpattern. For example, it looped when
204        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
205        condition was not nested. This bug has been fixed.
206    
207    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
208        past the start of the subject in the presence of bytes with the top bit
209        set, for example "\x8aBCD".
210    
211    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
212        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
213    
214    14. Optimized (?!) to (*FAIL).
215    
216    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
217        This restricts code points to be within the range 0 to 0x10FFFF, excluding
218        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
219        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
220        does: it's just the validity check that is more restrictive.
221    
222    16. Inserted checks for integer overflows during escape sequence (backslash)
223        processing, and also fixed erroneous offset values for syntax errors during
224        backslash processing.
225    
226    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
227        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
228    
229    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
230        caused an overrun.
231    
232    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
233        something other than just ASCII characters) inside a group that had an
234        unlimited repeat caused a loop at compile time (while checking to see
235        whether the group could match an empty string).
236    
237    20. Debugging a pattern containing \p or \P could cause a crash. For example,
238        [\P{Any}] did so. (Error in the code for printing property names.)
239    
240    21. An orphan \E inside a character class could cause a crash.
241    
242    22. A repeated capturing bracket such as (A)? could cause a wild memory
243        reference during compilation.
244    
245    23. There are several functions in pcre_compile() that scan along a compiled
246        expression for various reasons (e.g. to see if it's fixed length for look
247        behind). There were bugs in these functions when a repeated \p or \P was
248        present in the pattern. These operators have additional parameters compared
249        with \d, etc, and these were not being taken into account when moving along
250        the compiled data. Specifically:
251    
252        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
253            length.
254    
255        (b) An item such as \pL+ within a repeated group could cause crashes or
256            loops.
257    
258        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
259            "reference to non-existent subpattern" error.
260    
261        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
262    
263    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
264        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
265    
266    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
267    
268    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
269        character were causing crashes (broken optimization).
270    
271    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
272        \p or \P) caused a compile-time loop.
273    
274    28. More problems have arisen in unanchored patterns when CRLF is a valid line
275        break. For example, the unstudied pattern [\r\n]A does not match the string
276        "\r\nA" because change 7.0/46 below moves the current point on by two
277        characters after failing to match at the start. However, the pattern \nA
278        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
279        the same is true. There doesn't seem any very clean way out of this, but
280        what I have chosen to do makes the common cases work: PCRE now takes note
281        of whether there can be an explicit match for \r or \n anywhere in the
282        pattern, and if so, 7.0/46 no longer applies. As part of this change,
283        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
284        pattern has explicit CR or LF references.
285    
286    29. Added (*CR) etc for changing newline setting at start of pattern.
287    
288    
289    Version 7.2 19-Jun-07
290  ---------------------  ---------------------
291    
292   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,

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